Influence Points Bug

I look at my IP: 8068, time to buy another champ. After a while I decide that i will buy blitzcrank so i can save my ip for another later champ. I go to the shop, buy blitzcrank. Then I look up at my ip and see it at 1768. My first thought: maybe Blitzcrank actually costed 6300. I check the store, see that blitz still cost 3150 ip. I'm thoroughly confused at this point, so I restart my client, and voila, my ip is back to 4918. This obviously isnt a complaint post, but it is a bug, so I'm putting it here.